Switch construction



I United States Patent 1 13,548,137

[72] Inventors Guy M. Farrell [56] References Cited Elmhursl; UNITEDSTATES PATENTS P 2,432,367 12 1947 Andresen ZOO/61.04 N.Wh1tlock,Elmhurst;Martin Gaber, 2 835 754 5/1958 loo/166w] )UX 2] A l Ngg 2,932,698 4/1960 Barden 200/67(C)X f J 20 1968 3,030,459 4/1962Elliott et al 200/6(A) E gf 15'1970 3,255,319 6/1966 Paine...200/l66(SD)X 9 [73] Assignee Chicago Switch, Inc. 3,274,355 9/ 1966Francy 200/]66(.l )X

Chicago, Ill. Primary Examiner-Robert K. Schaefer a corporation ofIllinois Assistant Examiner Robert A. Vanderhye AltorneyMcDougall,Hersh, Scott and Ladd [54] SWlTCl-l CONSTRUCTION Claims 11 Drawing FigsABSTRACT: A switch construction including a movable ac- [52] US. Cl200/153, tuating means and a spring-loaded contact movable by said ac-200/166, 102/70, ZOO/61.04 tuating means. A contact end is positionedagainst a first ban-i1 [51] lnt.Cl H0lh 1/06, er, and this barrier isremoved upon initial movement of the HOlh 35/42 actuating means at whichtime the contact end is positioned [50] Field of Search 200/ 16681,against a second barrier. A distinct movement of the actuating 16684,61.04, 67C, 153, l66SD, 6A, 166.], 153, 153.9; l02/70.2

means results in removal of the second barrier, and movement of thecontact end to a closed contact position.

PATENTED DEB] 5197B SHEET 2 (IF 3 SWITCH CONSTRUCTION This inventionrelates to an improved switch construction. The switch construction tobe described is particularly suitable for use in applications requiringminiaturized components which have highly reliable operatingcharacteristics. When considering the following description, however, itwill be appreciated that the concepts can be adapted to larger scaleapplications.

It is a general object of this invention to provide an improved switchconstruction which will operate in a highly reliable fashion even whenproduced on a miniature scale.

It is a more particular object of this invention to provide a switchconstruction of the type referred to which is particularly adaptable foroperation in response to changes in the environmental conditions towhich the switch construction is exposed.

These and other objects of this invention will appear hereinafter andfor purposes of illustration, but not of limitation, specificembodiments of the invention are shown in the accompanying drawings inwhich:

FIG. 1 is a plan view of the switch construction;

FIG. 2 is a front elevational view partly cut away;

FIG. 3 is a side elevation partly cut away;

FIG. 4 is a vertical sectional view illustrating the switch constructionin combination with a housing, and including internal mechanisms adaptedto effect operation of the switch in response to environmental changesto which the assembly is exposed;

FIG. Sis an enlarged sectional view illustrating the movements of thecontact means in the course of the switch operation;

FIGS. 6, 7 and 8 comprise enlarged sectional views illustrating therespective positions of the contact means in the course of switchoperation;

FIG. 9 is a plan view illustrating an alternative form of the invention;

FIG. 10 is a front elevation of the construction shown in FIG. 9; and, 7

FIG. 11 is a side elevation of the construction shown in FIG. 9.

The switch construction of this invention generally comprises a movableactuating means and a spring-loaded contact movable by the actuatingmeans. The contact is adapted to bear against a first barrier in aninitial position of the switch. Upon movement of the actuating means,the first barrier is removed, and thereafter the contact is held by' asecond barrier. A separate, distinct movement of the actuating meanswill result in removal of the second barrier whereby the switch contactwill be moved to a new position which, in most applications, willcomprise the closed position of the switch.

One particular application for the switch of this invention involvesactuation by an element subject to environmental changes. It isspecifically contemplated that use of a material, such as siliconerubber, which in the dry state, will occupy a certain confined space.Upon exposure to a fluid, for example alcohol, the silicone rubber willexpand to a substantial degree and when properly associated with aswitch of this invention, the expansion will result in movement. of theactuating member of the switch. If the construction is then exposed tothe atmosphere, the alcohol will gradually evaporate whereby thesilicone rubber will contract thereby resulting in a distinct movementof the actuating means. i

In a typical application, the switch construction is set with the springloaded contact means pressing against a first barrier, this conditioncomprising a safe switch condition. The initial expansion of thesilicone rubber will result in movement of the contact whereby the firstbarrier can be overcome and whereby the contact will snap into positionadjacent a second barrier. This will comprise the ready condition of theSwitch.

The closing of the switch is accomplished during contraction of thesilicone rubber at which time the contact end overcomes the secondbarrier and snaps into position against a stationary contact. Thislatter position may be the bum position of the switch.

The switch can be used for military applications where it is ultimatelyto be included in a circuit for setting off an explosive charge. Thesafe position is desired so that handling of the switch will not resultin accidental setting off of the charge. In the arrangement described,this safe condition can be maintained as long as the silicone rubber iskept in a substantially v dry state. i

The ready condition is desired so that timing control of 'a sort can beachieved. Thus, switches of the type described can be placed in theready condition by immersing them in a suitable solution. The switcheswill remain in this ready condition as long as they remain in thesolution. In addition, the timing with respect to movement to the burnposition can be determined with a fair degree of accuracy since theevaporation rate can be measured.

FIGS; 1 through 8 illustrate a construction 10 comprising one example ofa switch arrangement characterized by the features of this invention.The switch includes an insulating base 12 having wire leads 14 extendingthrough the base. A housing 16 is supported by the base for enclosingthe switch components and actuating means.

One of the leads 14 includes a bent over portion 18 with the end of thelead being secured to the support 12 at 20. A second lead 14 includes anupper end 22 which is received within cylindrical sections 24 defined byan escapement element 26. The upper end 28 of a different lead 14contacts an interior wall of the escapement 26, and the escapement iswelded to the lead portions 24 and 28.

A center post 30 is mounted on the support 12, and a coil spring 32extends around this post. One end 34 of the coil spring bears againstthe lead portion 18. In the operation of the specific switch described,the lead 18 constitutes a common connection, and the coil spring 32comprises a movable contact element. The opposite end 36 of the springcomprises the movable contact portion, and a connection with the leadportion 18 will always be maintained irrespective of the position of thecontact end 36.

The escapement 26 includes a first cutout portion 38, and this cutoutportion is separated from a second cutout portion 40 by means of a strip42. The escapement 26 is preferably conductive material, and in theembodiment shown, the lead portion 24 constitutes a ground connection.When the contact end 36 is in the position shown in FIG. 5, the commonlead portion 18 will be connected to ground.

The actuating means for the switch comprises a strip 44 having one end46 secured to the support 12. The opposite end 48 of the strip definesan opening 50 for receiving the center post 30. A pair of ears 52 ismounted on the strip 44, and these cars extend into contact with aninverted cap 54. An annular element 56 is received within'the cap, andthis element may comprise silicone rubber which is adapted to absorbcertain liquids. Openings 58 are defined by the housing 16 wherebyliquids can enter into contact with the silicone rubber, and so thatevaporation can take place. The edges of the cap are sealed as shown asat 60 with respect to the housing 16 to prevent entry of liquids intothe section of the housing confining the switch 10.

The bottom surface of the strip 44 bears against the upper turn of thecoil spring 32. When a suitable solution is introduced through theopenings 58 into contact with the silicone rubber 56, expansion willtake place. The sealing material 60 permits downward movement of the cap54. An engagement of the cap with the cars 52 will cause the strip 44 topivot downwardly. This results in compression of the spring 32, anddownward movement of the contact end 36.

The contact end 36 initially bears against the edge 62 defined by thecutout portion 38. This edge forms a first barrier to movement of thecontact end 36. However, if the contact end is moved downwardly, it willride against the edge 62 and eventually engage the strip 42. This stripis preferably weakened at 64 whereby the contact end will cause thestrip 42 to break off so that the contact end can bypass the edge 62 andmove to the left as shown in FlG. 7.

When moved in the manner described, the contact end 36 will bepositioned against an edge 66 defined by the cutout portion 40. Thisedge forms a second barrier to the movement of the contact end. When thesilicone rubber 56 contracts due to evaporation of the solution absorbedtherein, the contact end will begin upward movement while bearingagainst the edge 66. Eventually the barrier presented by this edge isovercome whereby the contact end will shift to the position shown inFIG. 8.

In the position shown in FIG. 8, the contact end bears against an edge68 defined by a conductive member 70 secured to an upper portion 72 ofone of the leads M. This lead is electrically separated from all of theother leads and, therefore, when the contact end 36 is in the positionshown in FIG. 8, a completely new electrical circuit is introduced.

The switch position of FIG. 6 constitutes a safe position for theswitch. Thus, the contact end is connected to ground, and even if thecontact is moved beyond the barrier presented by the edge 62, a changein electrical condition will not result. Thus, movement of the contactend to the position shown in FIG. 7 still maintains connection throughground.

The position shown in FIG. 7 is the ready" position since movementbeyond the barrier presented by the edge 66 will result in a change inelectrical condition. Specifically, the further movement of the contactend 36 will result in contact with the element 70 whereby the groundconnection is broken and whereby a burn" position can be achieved.

In the fabrication of the switch, the escapement 26 can be formed from aflat sheet of conductive material and then cut out in the mannerillustrated. The escapement is then bent into shape and welded to thelead portions 24 and 28 as illustrated. The contact element 70preferably consists of an integral part of the escapement 26 until theescapement is attached to the lead portions. Thus, as shown by thedotted lines 74 in FIG. 6, the contact element 70 may form a connectedpart of the escapement 26, and this contact element can be welded to thelead portion 72 at the same time as the other escapement portions areattached to the lead portions 24 and 28. The separation between thecontact element 70, and the main body of the escapement can then be madewith a suitable cutting instrument.

The switch construction of FlGS. I through 8 includes a resettingfeature. The resetting is accomplished through the use of an extension78 formed integrally with the strip 44. This extension hangs over theupper edge 80 of the escapement 26. if fluid is returned into contactwith the silicone rubber 56, expansion will again occur, and theextension 78 will be moved downwardly into contact with the escapement.This will short out the switch, and this condition will remain as longas the silicone rubber remains in the expanded state. When evaporationoccurs, the extension 78 will withdraw whereby the burn position of theswitch will again become operative. The switch can be reset any numberof times with an arrangement of this type.

It will be appreciated that the operating principals of the switchdescribed are not dependent upon the use of the ac tuating arrangementconsisting of the the silicone rubber and cap 54. Thus, a simple manualswitch operation is clearly possible. Furthermore, it will be noted thatleads 14 which are connected to ground in the embodiment illustratedcould be otherwise connected to serve various electrical functions.Obviously, the switch could also be employed as a normally closed switchwith the contact element 70 serving as a ground or open connection.Finally, different electrical functions could be accomplished due tomovement of the contact end 36 beyond the first barrier. Thus, theescapement 26 could be separated between these barriers, and the readyposition utilized to serve a specific electrical function, for example,to actuate a warning light.

A modified form of the invention is shown in FIGS. 9 through 11. Thisconstruction includes a base 90 having leads 92, 94, 96, 98 and 100extending therethrough. A contact spring 102 is located around centerpost 104. One end 106 bears against the lead 92 which may comprise acommon connection. The opposite end 108 of the contact spring comprisesa movable contact portion.

In a position corresponding to the "safe position described, the contactend 108 bears against a first barrier provided by a hook portion 110formed in the lead 100. When the contact end 108 is pressed downwardly,for example, by actuating means of the type previously described, thecontact end will snap into engagement with the lead 98. Upward movementwill cause the contact end to snap into engagement with the lead 96. Thelead 98 provides a ready" position, and the lead 96 a burn" position.The lead 96 is bent over as shown at 112 to confine the contact 108adjacent the upper portion of the lead when the actuating means hasundergone the return movement for shifting the contact to the burnposition.

A resetting capability is also provided in this modified form of theinvention. The lead 94 is positioned along side the lead 96, and in theburn position, the contact end 108 will not engage the lead 94.Resetting movement of the actuating means will, however, cause thecontact end 108 to move downwardly, and this will drive the contact endinto engagement with the lead 94. The lead 94 then acts as a cam to movethe contact end out of engagement with the lead 96. Return movement ofthe actuating means will, of course, return the switch to the burnposition. Any number of resetting opera tions can be accomplished.

The switch design of FIGS. 9 through 11 presents certain advantages. Theelectrical leads themselves form the barriers, and contact-engagingsurfaces whereby assembly operations such as are required where theescapement is used can be eliminated. In addition, each of the leads canbe easily electri' cally insulated from the others whereby greatversatility from the standpoint of electrical function of the switchesis available.

The arrangement shown in FIGS. 9 through 11 can be easily modifiedwithout departing from the basic spirit of the switch design. Forexample, the switch described is essentially a three-step switch;however, additional steps can be interposed without difficulty therebyadding to the versatility of the switch. For example, a lead such as thelead 100 could be interposed between the leads 96 and 98 whereby thehook portion H0 would engage the contact 108 after the contact overcomesthe barrier presented by the lead 98. Subsequent downward movement willthen result in movement of the contact 108 on to the next barrier whichmay be an intermediate barrier such as the lead 98 or a final barriersuch as a lead 96. Where a lead similar to the lead 100 is employed asan intermediate barrier, it will be understood that the vertical sectionof the lead must be out of the path of the contact end 108 so as tointerfere with this contact end.

It will be understood that various other changes and modifications maybe provided in switch constructions of the type described which providethe characteristics of this invention without departing from the spiritthereof particularly as defined in the following claims.

We claim:

1. A switch construction comprising a movable actuating means, a contactelement movable by said actuating means, said contact element comprisinga coil spring, one end of said spring being stationary and in contactwith a common electrical connection, the other end of said springcomprising a movable contact, a first barrier holding said contactelement in a first position, initial movement of said actuating meansoperating to compress said spring and to thereby move said movablecontact, said first barrier comprising a first protruding contact pinextending outwardly from said support, said initial movement causingsaid movable contact to move beyond the end of said first pin and tothereby put said contact element in a ready condition, and a secondbarrier holding said contact element while in said ready condition, saidsecond barrier comprising a second protruding contact pin extendingoutwardly from said support, and wherein additional movement of saidactuating means in a direction different than said initial movementcauscs said movable contact to move beyond the end of said second memberand to snap under spring action into contact with a third contact pin ata new position of the switch, said contact element being included in acommon electrical circuit when engaged with said first and second pins,with said third pin being included in a different circuit.

2. A switch construction according to claim 1 wherein the opposite endsof said pins extend outwardly from the opposite side of said support,said opposite ends providing means for including the pins in electricalcircuits.

3. A switch construction according to claim 1 including a resetting pinmounted on said support adjacent said third contact pin, and whereinrecycling of said actuating means in the direction of said initialmovement operates to move said movable contact into engagement with saidresetting pin and out of engagement with said third pin, and whereinreturn movement of said actuating means in a different directionoperates to return said movable contact into engagement with said thirdpin and out of contact with said resetting pin.

4. A switch construction according to claim 3 wherein said resetting pinis included in an electrical circuit different than said third pin.

5. A switch construction comprising a support, a plurality of upstandingbarrier means carried on said support, a springloaded contact elementhaving a movable contact portion bearing against at least one of thebarrier means depending on the switch position, and an actuating meansfor moving said movable contact portion relative to said support, themovement of said actuating means in an initial direction operating tomove the contact portion over the surface of a first barrier and beyondthe end of the barrier whereby the contact portion will snap intoposition against a second barrier, and wherein the switch operationincludes at least one additional movement of said actuating means in adifferent direction which operates to move said contact portion over thesurface of said second barrier and beyond the end of said second barrierwhereby the contact end snaps into position adjacent a third barrier,each of said barriers including means attached to and extendingoutwardly from said support, and wherein at least one of said barriersis conductive thereby operating to include said movable switch portionin an electrical circuit.

6. A switch construction comprising a movable actuating means, a contactelement movable by said actuating means, said contact element comprisinga coil spring, one end of said spring being stationary and in contactwith a common electrical connection, the other end of said springcomprising a movable contact, a first barrier holding said contactelement in a first position, initial movement of said actuating meansoperating to compress said spring and to thereby move said movablecontact, said initial movement causing said movable contact to movebeyond said first barrier and to thereby put said contact element in aready condition, and a second barrier holding said contact element whilein said ready condition, and wherein additional movement of saidactuating means in a direction difierent than said initial movementcauses said movable contact to move beyond said second barrier and tosnap under spring action to new position of the switch, said contactelement being included in a common electrical circuit when engaged withsaid first and second barriers, and said contactelement being includedin a different circuit when in said new position, and including anescapement part mounted on said support and formed of conductivematerial, said first and second barriers comprising protruding portionsformed by cutouts defined by the escapement, and including a thirdprotruding member carried by said support forming said new position.

7. A switch construction according to claim 6 wherein said escapement isformed from a strip of conductive material, and wherein said thirdprotruding member initially constitutes a section of said strip wherebythe strip can be mounted as a unit on said support, and including acomplete separation cutout between said third portion and the main bodyof said strip after mounting of the strip on said support.

8. A switch construction according to claim 6 including a contact armcarried by said actuating means, and wherein recycling movement of saidactuating means in the direction of said initial movement operates tomove said contact arm into contact with the escapement part definingsaid first and second barriers, said contact arm being electricallyconnected to said movable contact to provide a short circuit throughsaid escapement part and through the movable contact.

9. A switch construction according to claim 6 wherein the cutoutdefining said first barrier is separated from the cutout defining thesecond barrier by means of an elongated arm portion forming a part ofsaid escapement, and wherein the movable contact within said first cutout bears against said elongated arm in response to movement of saidactuating means and eventually forces said elongated-arm out of the wayas the movable contact overcomes the first barrier and moves intoposition against the second barrier.

10. A switch construction comprising a support, a switchactuating meansmovable relative to said support, a springloaded contact elementengageable by said actuating means for movement therewith, first andsecond barriers each defining a contact-engaging surface said barriersbeing mounted in stationary positions relative to said support, thefirst barrier extending in a position away from said support and thesecond barrier extending in an opposite direction relative to saidsupport, each of said barriers terminating in a free end, saidspring-loaded contact element pressing against the contactengagingsurface of one of said barriers in one position of said switch, movementof said actuating means in one direction relative to said support,operating to drive said spring-loaded contact element beyond the freeend of said one barrier, said spring-loaded contact element then movingto a second position of said switch by snapping into pressure engagementwith the other barrier, movement of said actuator means in a differentdirection relative to said support operating to drive said spring-loadedcontact element beyond the free end of said other barrier, a thirdposition of said switch, said spring loaded contact element moving tosaid third position when it has been moved beyond said free end of saidother barrier.

11. A switch construction comprising a movable actuating means, acontact element movable by said actuating means,

said contact element comprising a spring having a movable portion and anend portion held stationary and in contact with a common electricalconnection, a first barrier holding said movable contact portion in afirst position, initial movement of said actuating means operating tocompress said spring and to thereby move said movable contact portion,said first barrier comprising a first protruding contact memberextending outwardly from said support, said initial movement causingsaid movable contact portion to move beyond the end of said firstprotruding member and to thereby put said contact element in a readycondition, and a second barrier holding said contact element while insaid ready condition, said second barrier comprising a second protrudingcontact member extending outwardly from said support, and whereinadditional movement of said actuating means in a direction differentthan said initial movement is required to move said movable contactportion beyond the end of said second protruding member and to snapunder spring action into contact with a third contact member at a newposition of the switch, said contact element being included in a commonelectrical circuit when engaged with said first and second members, withsaid third member being included in a different circuit.

12. A switch construction comprising a support, a switchactuating meansmovable toward and away from said support, a spring-loaded contactelement engageable by said actuating means for movement with theactuating means toward and away from the support and for movementtransversely of the support, first and second barriers each defining acontact-engaging surface, said barriers being mounted in stationaryposition of said switch by snapping into pressure engagement with theother barrier. movement of said actuator means in the opposite directionrelative to said support operating to drive said spring-loaded contactelement beyond the free end of said other barrier thereby releasing saidspring-loaded contact from engagement with said other barrier, andincluding a third position of said switch, said spring-loaded contactelement moving to said third position when it has been released fromsaid other barrier

